Precisely what happened in Iberia in the early 8th century is much uncertain. There is one contemporary Christian source, the Chronicle of 754 (which ends on that date), regarded as reliable but often vague. There are no contemporary Muslim accounts. What Muslim information there is comes from later compilations, which are much coloured by the writers' sense of what was proper, and by contemporary politics—the most prominent such compilation is that of Al-Maqqari, which dates from the 17th century. This paucity of sources means that any specific or detailed claims need to be regarded with caution.

What are available are a number of stories that might more properly be described as legends. The manner of King Roderic's ascent to the throne is unclear; there are accounts of dispute with Achila II, son of his predecessor Wittiza, and accounts that Wittiza's family fled to Tangier and solicited help from there. Numismatic evidence suggests a division of royal authority, with several coinages being struck, and Achila II remaining king on the Tarraconsense (the Ebro basin) and Septimania until 713 (or more probably 714).

There is also a story of one Julian, count of Ceuta, whose wife or daughter was raped by Roderic and who also sought help from Tangier. However, these stories are propagandistic and not included in the earliest accounts of the conquest.[1]

As to the initial nature of the expedition, historical opinion takes four directions: (1) that a force was sent to aid one side in a civil war in the hope of plunder and a future alliance; (2) that it was a reconnaissance force sent to test the military strength of the Visigothic kingdom; (3) that it was the first wave of a full–scale invasion; (4) that it was an unusually large raiding expedition with no direct strategic intentions.

In 711, a raiding force from North Africa approximately 1,700-strong led by Tariq Ibn Ziyad, landed south of present-day Spain.[2]Ibn Abd-el-Hakem reports, one and a half centuries later, that "the people of Andalus did not observe them, thinking that the vessels crossing and recrossing were similar to the trading vessels which for their benefit plied backwards and forwards." They defeated the Visigothic army, led by King Roderic, in a decisive battle at Guadalete in 712. Tariq's forces were then reinforced by those of his superior, the waliMusa ibn Nusair, and both took control of most of Iberia with an army estimated at approximately 10,000–15,000 combatants.[3]

According to Muslim historianMuhammad ibn Jarir al-Tabari,[4] Iberia was first invaded some sixty years earlier during the caliphate of Uthman (Rashidun era). Another prominent Muslim historian of the 13th century, Ibn Kathir,[5] quoted the same narration, pointing to a campaign led by Abd Allah bin Nafi al Husayn and Abd Allah bin Nafi al Abd al Qays[6] in 32th Hijra year. However, these early approaches are not taken into account nowadays.

The conquering army was made up mainly of Berbers who had themselves only recently come under Muslim influence. It is probable that this army represented a continuation of a historic pattern of large-scale raids into Iberia dating to the pre–Islamic period, and hence it has been suggested that actual conquest was not originally planned. Both the Chronicle and later Muslim sources speak of raiding activity in previous years, and Tariq's army may have been present for some time before the decisive battle. It has been argued that this possibility is supported by the fact that the army was led by a Berber and that Musa, who was the Umayyad Governor of North Africa, only arrived the following year — the governor had not stooped to lead a mere raid, but hurried across once the unexpected triumph became clear. The Chronicle of 754 states that many townspeople fled to the hills rather than defend their cities, which might support the view that this was expected to be a temporary raid rather than a permanent change of government.

The Chronicle of 754 stated that "the entire army of the Goths, which had come with him [Roderic] fraudulently and in rivalry out of hopes of the Kingship, fled". This is the only contemporary account of the battle and the paucity of detail led many later historians to invent their own. The location of the battle is not totally clear but was probably the Guadalete River.

Roderic was believed to have been killed and a crushing defeat would have left the Visigoths largely leaderless and disorganized. In this regard, the ruling Visigoth population is estimated at a mere 1 to 2% of the total population,[7] which on one hand led to 'a reasonably strong and effective instrument of government’; however, it was highly 'centralised to the extent that the defeat of the royal army left the entire land open to the invaders’.[8] The resulting power vacuum, which may have indeed caught Tariq completely by surprise, would have aided the Muslim conquest immensely. Indeed it may have been equally welcome to the Hispano-Roman peasants who, as D.W. Lomax claims were disillusioned by the prominent legal, linguistic and social divide between them and the 'barbaric' and 'decadent' Visigoth royal family[9]

In 714, Musa ibn Nusayr headed north-west up the Ebro river to overrun western Basque regions and the Cantabrian mountains all the way to Gallaecia, with no relevant or attested opposition. During the period of the second (or first, depending on the sources) Arab governor Abd al-Aziz ibn Musa (714–716) the principal urban centres of Catalonia surrendered. In 714, his father Musa ibn Nusair advanced and overrun Soria, western Basque regions, Palencia, and Asturias all the way to the coastal town of Gijón, where a Berber governor was appointed (or possibly in León) with no relevant or attested opposition. The northern areas of Iberia drew little attention to the conquerors and were hard to defend when taken. The high western and central sub-Pyrenean valleys remained unconquered.

At this time Umayyad troops reached Pamplona, and the Basque town submitted after a compromise was brokered with Arab commanders to respect the town and its inhabitants, a practice that was common in many towns of the Iberian Peninsula.[10] The Umayyad troops met little resistance. Considering that era's communication capabilities, three years was a reasonable time spent almost reaching the Pyrenees, after making the necessary arrangements for the towns' submission and their future governance.[11]

Northwestern al-Andalus, the Pyrenees and southern Gaul at the time of the Berber rebellion (739–742)

In 713, Abd al-Aziz ibn Musa subdued the forces of the Visigothic count Theudimer (or Tudmir), who had taken over southeastern Iberia from his base in Murcia after the power vacuum following king Roderic's defeat. Theudimer then signed a conditional capitulation by which his lands were made into an autonomous client state under Umayyad rule ("the rule of God"). His government and Christian beliefs of his subjects were respected; in exchange he pledged to pay a tax and to hand over any rebels plotting against Umayyad rule or Islamic religion. In this way, the life of many inhabitants remained much the same as before Tariq's and Musa's campaigns.[12] The treaty signed with Theudimer set a precedent for the whole of Iberia, and towns surrendering to Umayyad troops experienced a similar fate, including probably the muwalladBanu Qasi based in the Ebro valley, and other counts and landowners.

In exception to this pattern, some towns (Cordova, Toledo, etc.) were stormed and captured unconditionally by the Umayyads, to be governed by direct Arab rule. In the area thought to be part of King Roderic's territory, Mérida staged also a prolonged resistance to the Umayyad advance, but was ultimately conquered in mid-summer 712.[13] As of 713 (or 714), the last Visigothic king Ardo took over from Achila II, with an effective control just over Septimania, and probably the eastern Pyrenean threshold and coastal areas of the Tarraconense.

Islamic laws did not apply to all the subjects of the new rulers. Christians were ruled by their own Visigothic law code (Forum Iudicum) as before. In most of the towns ethnic communities remained segregated and newly arriving ethnic groups (Syrians, Yemenites, Berbers and others) would erect new boroughs outside existing urban areas. However, this would not apply to towns under direct Umayyad rule. In Cordova, the Cathedral was partitioned and shared to provide for the religious needs of Christians and Muslims. This situation lasted some 40 years until Abd ar-Rahman's conquest of southern Spain (756).

An early governor (wali) of al-Andalus, al-Hurr ibn Abd al-Rahman al-Thaqafi, spread the rule of the Umayyad Caliphate up to the Ebro valley and the northeastern borders of Iberia, pacifying most of the territory and initiating in 717 the first forays across the Pyrenees into Septimania. In addition, he laid out the foundations of Umayyad civil administration in Iberia, by sending civil administration officials (judges) to conquered towns and lands guarded by garrisons established usually next to the population nuclei.[14] Moreover, al-Hurr restored lands to their previous Christian landowners, which may have added greatly to the revenue of the Umayyad governors and the caliph of Damascus, since only non-Muslims were subject to taxation. The task of establishing a civil administration in conquered al-Andalus was essentially completed by the governor Yahya ibn Salama al-Kalbi 10 years later.

The period following al-Hurr's office saw the establishment of the Arabs in southern Septimania during Al-Samh ibn Malik al-Khawlani's tenure as wali. Narbonne fell (720), and no sooner had he garrisoned it than the Arab commander led an offensive against Toulouse. During this Umayyad thrust or its aftermath, King Ardo died (721).

On the first stage of the invasion the armies were made up of Berbers and different Arab groups. These peoples clustered around the banner of the Umayyads didn't mix together, but remained in separate towns and boroughs. The Berbers, recently subdued and superficially Islamized, were usually in charge of the most difficult tasks and the most rugged terrains, similar to the ones found in their homeland of north Africa, while the Arabs occupied the more gentle plains of southern Iberia.[15]

Consequently, the Berbers went on to station in Galicia (possibly including Asturias) and the Upper Marches (Ebro basin), but these lands remained unpleasant, humid and cold. The grievances resented by the Berbers under Arab rulers (attempts to impose a tax on Muslim Berbers, etc.) sparked rebellions in north Africa that expanded into Iberia. An early uprising took place in 730, when Uthman ibn Naissa (Munuza), master of the eastern Pyrenees (Cerretanya), allied with the duke Odo of Aquitaine and detached from Cordova.

Those internal frictions continually threatened (or sometimes may, paradoxically, have spurred) the Umayyad ever-expanding military effort in al-Andalus during the conquest period. Circa 739, on learning the news of Charles Martel's second intervention in Provence, Uqba ibn al-Hajjaj had to call off an expedition to the Lower Rhone in order to deal with the Berber Revolt in the south instead. Later next year, the Berber garrisons stationed in León, Astorga and other north-western outposts gave up their positions, and some of them even embraced the Christian religion.[16] The Muslim settlement was thereafter established permanently south of the Douro's banks.

The Berber rebellions swept the whole al-Andalus under Abd al-Malik ibn Katan al-Fihri's term as governor. Reinforcements were then called from the other end of the Mediterranean in a military capacity: the "Syrian" junds (actually Yemeni Arabs). The Berber rebellions were quelled in blood, and the Arab commanders came up reinforced after 742. Different Arab factions reached an agreement to alternate in office, but this didn't last long, since Yusuf ibn 'Abd al-Rahman al-Fihri (opposed to the Umayyads) remained in power up to his defeat by Abd-ar-Rahman I in 756, and the establishment of the independent Umayyad Emirate of Cordova. It is in this period of unrest that the Frankish king Pepin could finally capture Narbonne from the Andalusians (759).

In Yusuf's and Abd-ar-Rahman's fight for power in al-Andalus, the "Syrian" troops, a mainstay of the Umayyad Caliphate, split. For the most part, Arabs from the Mudhar and Qais tribes sided with Yusuf, so did the indigenous (second or third generation) Arabs from northern Africa, while Yemeni units and some Berbers took sides with Abd-ar-Rahman, probably born to a north African Berber mother himself. In 756, south and central al-Andalus (Cordova, Sevilla) were in the hands of Abd-ar-Rahman, but it took still 25 years for him to hold sway over the Upper Marches (Pamplona, Zaragoza and all the northeast).[17]

The Iberian Peninsula was but the westernmost tip of the Umayyad Caliphate of Damascus and was under the rule of the governor of Ifriqiya. In 720 the caliph even considered abandoning the territory. The conquest was followed by a period of several hundred years during which most of the Iberian peninsula was known as Al-Andalus, dominated by Muslim rulers. Only a handful of new small Christian realms managed to reassert their authority across the faraway mountainous north of the peninsula.

In 756, Abd ar-Rahman I, a survivor of the then-recently overthrown Umayyad Dynasty, landed in al-Andalus and seized power in Cordova and Seville, proclaimed himself emir or malik, by removing any mentions of the Abbasid Caliphs of Damascus from the Friday prayers.[18] In the wake of these events, southern Iberia became de jure and de facto independent from the Damascus Caliphate. Although this was not accepted outside al-Andalus and those North African territories with which it was affiliated, Abd ar-Rahman I, and especially his successors, considered that they were the legitimate continuation of the Umayyad caliphate, i.e. that their rule was more legitimate than that of the Abbasids. It seems that Abd ar-Rahman I never considered establishing a separate principality, but reconquering the Damascus Caliphate instead. (See Caliphate of Cordova.)

During the unification of al-Andalus in the reign of Abd ar-Rahman I before his death in 788, al-Andalus underwent centralization and slow but steady homogenization. The autonomous status of many towns and regions negotiated in the first years of the conquest was reversed by 778,[19] in some cases much earlier (Pamplona by 742, for example). The Hispanic Church based in Toledo, whose status remained largely undiminished under the new rulers, fell out with the Roman Church during the Adoptionist controversy (late 8th century). Rome relied on an alliance with Charlemagne (in war with the Cordovan emirs) to defend its political authority and possessions, and went on to recognize the northern Asturian principality (Gallaecia) as a kingdom apart from Cordova, and Alfonso II as king. The population of al-Andalus, especially local nobles who aspired to a share in power, began to embrace Islam and the Arabic language. However, the majority of the population remained Christian (using the Mozarabic Rite), and Latin (Mozarabic) remained the principal language until the 11th century.

Abd ar-Rahman I founded an independent dynasty that survived until the 11th century. That line was succeeded by a variety of short and small emirates (taifas) unable to stop the push of the expansionist northern Christian kingdoms. The Almoravids (1086-1094) and the Almohads (1146-1173) occupied al-Andalus next, and the Marinids in 1269, but that could not prevent the fragmentation of Muslim ruled territory. The last Muslim emirate, Granada was defeated by the armies of Castile (successor to Asturias) and Aragon under Isabella and Ferdinand in 1492. The last wave of expulsions from Spain of native population with Muslim descent took place in 1614.

^Rucquoi notes that the tale of Count Julian's wife or daughter does not appear in the Chronicle of 754 and considers it to be "probably a legend", but considers there may be more truth in the stories concerning Wittiza's family; Rucquoi, Adèle (1993), Histoire médiéval de la Péninsule ibérique, Éditions du Seuil, p. 71, ISBN2-02-012935-3